U.S. patent application number 11/761521 was filed with the patent office on 2008-12-18 for line-of-sight rfid tag reader.
Invention is credited to Ajang Bahar.
Application Number | 20080309494 11/761521 |
Document ID | / |
Family ID | 40131760 |
Filed Date | 2008-12-18 |
United States Patent
Application |
20080309494 |
Kind Code |
A1 |
Bahar; Ajang |
December 18, 2008 |
LINE-OF-SIGHT RFID TAG READER
Abstract
Provided by aspects of the invention are devices, systems and
methods for enabling the use of RFID tags that are not
unnecessarily complex by changing the arrangement and operation of
RFID tag readers Specifically, provided in some embodiments in
accordance with aspects of the invention is a RFID tag reader
incorporating a type of highly directional antenna, known as a
pencil beam antenna. In operation, a pencil beam antenna has a
highly focused and thinly shaped lobe. Those skilled in the art
will appreciate that an antenna lobe is the volume of space within
which RF signals can be detected and coupled to a receiver
connected to the pencil beam antenna or within which RF signals can
propagate after being transmitted by a transmitter connected to the
pencil beam antenna. The highly focused and thinly shaped lobe
created by the pencil beam antenna enables selective communication
with individual RFID tags, even those RFID tags incorporating
low-directivity antennas.
Inventors: |
Bahar; Ajang; (Kitchener,
CA) |
Correspondence
Address: |
HERMAN & MILLMAN
141 ADELAIDE ST. WEST, SUITE 1002
TORONTO
ON
M5H 3L5
CA
|
Family ID: |
40131760 |
Appl. No.: |
11/761521 |
Filed: |
June 12, 2007 |
Current U.S.
Class: |
340/572.7 ;
340/572.1 |
Current CPC
Class: |
H04B 5/0062 20130101;
H04B 5/00 20130101; H04B 5/0081 20130101 |
Class at
Publication: |
340/572.7 ;
340/572.1 |
International
Class: |
H04B 7/00 20060101
H04B007/00 |
Claims
1. A Radio Frequency Identification (RFID) tag reader comprising: a
highly-directional antenna operable to create a highly focused and
thinly shaped lobe, the lobe being the volume of space within which
Radio Frequency (RF) signals can be detected and coupled to the
RFID tag reader and also within which RF signals can propagate
after being transmitted by the RFID tag reader; a transmit signal
chain operable to produce a transmission signal at a RF frequency,
the transmit signal chain operably connectable to the
highly-directional antenna; a receive signal chain operable to
accept and down-convert a received signal at a RF frequency, the
receive signal chain operably connectable to the highly-directional
antenna for accepting the received signal at the RF frequency; and
a controller for managing the operation of the RFID tag reader, the
controller operably connected to the transmit and the receive
signal chains.
2. A RFID tag reader according to claim 1, further comprising a
user interface for permitting a user to direct the use of the RFID
tag reader, the user interface operably connectable to the
controller, wherein the controller accepts input instructions from
a user through the user interface and provides feedback to the user
through the user interface.
3. A RFID tag reader according to claim 2, wherein the user
interface includes at least one of a keypad, a display and a touch
screen.
4. A RFID tag reader according to claim 1, wherein the controller
is further connectable to another system employing the
functionality of the RFID tag reader.
5. A RFID tag reader according to claim 1, further comprising a
circulator for selectively connecting at least one of the transmit
signal chain and the receive signal chain to the highly directional
antenna.
6. A RFID tag reader according to claim 1, further comprising a
multiplexer for selectively connecting at least one of the transmit
signal chain and the receive signal chain to the highly directional
antenna.
7. A RFID tag reader according to claim 1, further comprising a
targeting element for aiming the highly focused and thinly shaped
lobe created by the highly-directional antenna.
8. A RFID tag read according to claim 7, wherein the targeting
element comprises a coherent light source that emits laser light
substantially through the center of the highly focused and thinly
shaped lobe created by the highly-directional antenna, wherein the
laser light is within the spectrum of visible light and in
operation serves as a guide for directing the highly focused and
thinly shaped lobe of the antenna.
9. A RFID tag reader according to claim 8, further comprising an
optical light emitter connected to the coherent light source, the
optical light emitter arranged in front of the highly-directional
antenna, whereby in operation, the laser light and the antenna lobe
overlap along the length of the antenna lobe.
10. A RFID tag reader according to claim 7, wherein the targeting
element comprises a viewfinder for aiming the highly focused and
thinly shaped lobe.
11. A method of operating a Radio Frequency Identification (RFID)
tag reader having a highly-directional antenna, the
highly-directional antenna operable to produce a highly-focused and
thinly shaped lobe, the method comprising: aiming the
highly-focused and thinly shaped lobe at a RFID tag; transmitting a
signal to the RFID tag; and receiving a signal back from the RFID
tag.
12. A method according to claim 11, further comprising visually
selecting the RFID tag with which communication is desired.
13. A method according to claim 11, further comprising using a
targeting element for aiming the highly focused and thinly shaped
lobe at the RFID tag.
14. A method according to claim 13, wherein the targeting element
includes one of a laser sight aligned with the highly focused and
thinly shaped lobe and a viewfinder.
15. A method according to claim 11, further comprising: receiving a
response including an authentication key from the RFID tag;
determining whether or not communication is permitted between the
RFID tag reader and the RFID tag based on evaluation of the
authentication key; indicating to the user the result of the
evaluation; and permitting communication depending on the result of
the evaluation.
16. A method according to claim 11, further comprising: receiving a
response including an authorization message from the RFID tag;
determining whether or not communication is permitted between the
RFID tag reader and the RFID tag based on evaluation of the
authorization message; indicating to the user the result of the
evaluation; and permitting communication depending on the result of
the evaluation.
17. A method according to claim 11, further comprising:
transmitting an authentication key to the RFID tag; receiving a
response including an authorization message from the RFID tag;
determining whether or not communication is permitted between the
RFID tag reader and the RFID tag based on evaluation of the
authorization message; indicating to the user the result of the
evaluation; and permitting communication depending on the result of
the evaluation.
Description
FIELD OF THE INVENTION
[0001] The invention relates to the use of Radio Frequency
Identification (RFID) tags, and in particular to a selective
communication with RFID tags.
BACKGROUND OF THE INVENTION
[0002] Radio Frequency Identification (RFID) tags provide a useful
way of labeling and tracking articles and containers. A RFID tag
can be programmed to contain information either during the
manufacture of the RFID tag and/or in the field after the RFID tag
has been affixed to an article or container. For example, a
particular RFID tag can programmed to contain information about the
contents of a container used for shipping (e.g. type of articles in
the container, quantity of each type of article, etc.). RFID tags
can function under a variety of environmental conditions and
provide a high level of data integrity, while also being cheap
enough to be considered disposable and easily replaceable. Yet more
complex RFID tags are typically more expensive. So the cost of RFID
tags is a factor considered in developing a system using RFID tags,
with unnecessarily complex RFID tags considered undesirable.
[0003] In use, information on a RFID tag is read (or written) using
modulated electromagnetic energy in the radio frequency bands. This
is accomplished by the creation of an ad hoc wireless communication
channel between a RFID tag reader and one or more RFID tags in a
particular area. Communication is initiated when the RFID tag
reader transmits a polling signal into a particular space
containing one or more RFID tags affixed to articles or containers
The RFID tags are designed to automatically respond to the polling
signal, providing information to the RFID reader.
[0004] An often relied upon advantage of a conventional RFID tag is
that the RFID tag does not require contact or a line-of-sight
wireless channel to communicate with a reader. To that end, the
antenna provided in a RFID tag typically has very low directivity
to ensure that the RFID tag can be read (or written to) without a
direct line-of-sight. More specifically, a typical RFID tag
includes an antenna that has a quasi-spherical (omni-directional)
beam pattern meaning that RF energy transmitted from the RFID tag
propagates in a quasi-spherical manner away from the RFID tag. In
some cases, an RFID tag includes a back plate to prevent RF energy
from propagating into or through an article or container that the
RFID tag is attached to, and instead is mostly directed away from
the article or container. Low-directivity antennas are often less
complex and cheaper to manufacture than more directional antennas,
which helps to keep the cost of RFID tags down.
[0005] RFID tag readers also typically have low-directivity
antennas, which also means that RF energy transmitted from the RFID
tag reader propagates in a quasi-spherical manner away from the
RFID tag reader. There are a number of advantages to providing a
RFID tag reader with a low-directivity antenna. First, the RFID tag
reader can be used to indiscriminately poll and receive information
from multiple RFID tags at the same time. Second, low-directivity
antennas provide for the flexible use and installation of a RFID
tag reader by not imposing strict requirements on the orientation
and positioning of the RFID tag reader.
[0006] The use of non-directional antennas does have disadvantages.
First, the information transmitted between the RFID tag and reader
may be easily intercepted and read by an unintended party. Second,
in a particular space containing numerous RFID tags it is difficult
to select a particular RFID tag to read or program (write to). For
example, in a warehouse containing multiple boxes, where each box
is labeled with a respective RFID tag, some of the RFID tags may
indicate that the same type of article is in a corresponding subset
of the boxes. However, there may be varying quantities of the
article in each of the subset of boxes. Using a conventional RFID
tag reader located within the warehouse (or in a hand-held device)
it is possible to determine the number of boxes with a particular
type of article that are in the warehouse, and even the number of
boxes with a particular quantity of the particular article.
However, it would be difficult to precisely locate those boxes
within the warehouse or read/program a RFID tag on a particular box
that is relatively close to other RFID tags. In order to locate
particular boxes or read/program a particular RFID tag to the
exclusion of others, the RFID tag reader must be positioned close
enough to a particular RFID tag to ensure that only that particular
RFID tag is being read/programmed. Alternatively, more complex and
more expensive RFID tags having batteries and more sophisticated
processing functions may be employed.
SUMMARY OF THE INVENTION
[0007] According to an aspect of an embodiment of the invention,
there is provided a Radio Frequency Identification (RFID) tag
reader including: a highly-directional antenna operable to create a
highly focused and thinly shaped lobe, the lobe being the volume of
space within which Radio Frequency (RF) signals can be detected and
coupled to the RFID tag reader and also within which RF signals can
propagate after being transmitted by the RFID tag reader; a
transmit signal chain operable to produce a transmission signal at
a RF frequency, the transmit signal chain operably connectable to
the highly-directional antenna; a receive signal chain operable to
accept and down-convert a received signal at a RF frequency, the
receive signal chain operably connectable to the highly-directional
antenna for accepting the received signal at the RF frequency; and
a controller for managing the operation of the RFID tag reader, the
controller operably connected to the transmit and the receive
signal chains.
[0008] In some embodiments, the RFID tag reader also includes a
user interface for permitting a user to direct the use of the RFID
tag reader, the user interface operably connectable to the
controller, wherein the controller accepts input instructions from
a user through the user interface and provides feedback to the user
through the user interface. In some more specific embodiments, the
user interface includes at least one of a key pad, a display and a
touch screen.
[0009] In some embodiments, the controller is further connectable
to another system employing the functionality of the RFID tag
reader.
[0010] In some embodiments, the RFID tag reader also includes a
circulator for selectively connecting at least one of the transmit
signal chain and the receive signal chain to the highly directional
antenna.
[0011] In some embodiments, the RFID tag reader also includes a
multiplexer for selectively connecting at least one of the transmit
signal chain and the receive signal chain to the highly directional
antenna.
[0012] In some embodiments, the RFID tag reader also includes a
targeting element for aiming the highly focused and thinly shaped
lobe created by the highly directional antenna. In some more
specific embodiments, the targeting element comprises a coherent
light source that emits laser light substantially through the
center of the highly focused and thinly shaped lobe created by the
highly-directional antenna, wherein the laser light is within the
spectrum of visible light and in operation serves as a guide for
directing the highly focused and thinly shaped lobe of the
antenna.
[0013] In some embodiments, the RFID tag reader also includes an
optical light emitter connected to the coherent light source, the
optical light emitter arranged in front of the highly-directional
antenna, whereby in operation, the laser light and the antenna lobe
overlap along the length of the antenna lobe.
[0014] In some embodiments, the targeting element comprises a
viewfinder for aiming the highly focused and thinly shaped
lobe.
[0015] According to an aspect of an embodiment of the invention,
there is provided a method of operating a Radio Frequency
Identification (RFID) tag reader having a highly-directional
antenna, the highly-directional antenna operable to produce a
highly-focused and thinly shaped lobe, the method including: aiming
the highly-focused and thinly shaped lobe at a RFID tag;
transmitting a signal to the RFID tag; and receiving a signal back
from the RFID tag.
[0016] In some embodiments, the method also includes visually
selecting the RFID tag with which communication is desired. In some
other embodiments, the method also includes using a targeting
element for aiming the highly-focused and thinly shaped lobe at the
RFID tag. In some even more specific embodiments, the targeting
element includes one of a laser sight aligned with the highly
focused and thinly shaped lobe and a viewfinder.
[0017] In some embodiments, the method also includes: receiving a
response including an authentication key from the RFID tag;
determining whether or not communication is permitted between the
RFID tag reader and the RFID tag based on evaluation of the
authentication key; indicating to the user the result of the
evaluation; and permitting communication depending on the result of
the evaluation.
[0018] In some embodiments, the method also includes: receiving a
response including an authorization message from the RFID tag;
determining whether or not communication is permitted between the
RFID tag reader and the RFID tag based on evaluation of the
authorization message; indicating to the user the result of the
evaluation; and permitting communication depending on the result of
the evaluation.
[0019] In some embodiments, the method also includes: transmitting
an authentication key to the RFID tag; receiving a response
including an authorization message from the RFID tag; determining
whether or not communication is permitted between the RFID tag
reader and the RFID tag based on evaluation of the authorization
message; indicating to the user the result of the evaluation; and
permitting communication depending on the result of the
evaluation.
[0020] Other aspects and features of the present invention will
become apparent to those ordinarily skilled in the art, upon review
of the following description of the specific embodiments of the
invention in accordance with either of the aspects described
above.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] For a better understanding of the present invention, and to
show more clearly how it may be carried into effect, reference will
now be made, by way of example, to the accompanying drawings, which
illustrate aspects of embodiments of the present invention and in
which:
[0022] FIG. 1 is a schematic view of a Radio Frequency
Identification (RFID) tag reader provided in accordance with
aspects of the invention;
[0023] FIG. 2 is an illustration depicting a method of use of a
RFID tag reader in accordance with aspects of the invention;
[0024] FIG. 3 is a first flow chart illustrating general method
steps for operating a RFID tag reader in accordance with aspects of
the invention; and
[0025] FIG. 4 is a second flow chart illustrating method steps for
operating a RFID tag reader in accordance with aspects of the
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0026] Radio Frequency Identification (RFID) tags provide a useful
way of labeling and tracking articles and containers. However, the
incorporation of low-directivity antennas in RFID tags and RFID tag
readers makes it difficult to select a particular RFID tag to read
or program (write to) to the exclusion of others. The use of
low-directivity antennas also makes it difficult to prevent
communication between a RFID tag and a RFID tag reader from being
intercepted and read by an unintended party. Prior efforts to
overcome these and related issues result in RFID tags of increased
complexity, which in turn often increases the cost of the RFID
tags. In the design of a system using RFID tags it would be
preferable to use lower-cost RFID tags when it is feasible, since
such systems employ significant numbers of RFID tags and many of
those RFID tags will likely be replaced due to damage, loss or
being discarded.
[0027] Provided by aspects of the invention are devices, systems
and methods for enabling the use of RFID tags that are not
unnecessarily complex by changing the arrangement and operation of
RFID tag readers. Specifically, provided in some embodiments in
accordance with aspects of the invention is a RFID tag reader
incorporating a type of highly-directional antenna, known as a
pencil beam antenna. In operation, a pencil beam antenna has a
highly focused and thinly shaped lobe. Those skilled in the art
will appreciate that an antenna lobe is the volume of space within
which RF signals can be detected and coupled to a receiver
connected to the pencil beam antenna or within which RF signals can
propagate after being transmitted by a transmitter connected to the
pencil beam antenna. The highly focused and thinly shaped lobe
created by the pencil beam antenna enables selective communication
with individual RFID tags, even those RFID tags having
low-directivity antennas.
[0028] Additionally and/or alternatively, in some embodiments a
RFID tag reader provided in accordance with aspects of the
invention also includes a targeting element for aiming the highly
focused and thinly shaped lobe created by the pencil beam antenna.
Specifically, in one embodiment, an RFID tag reader includes a
coherent light source (or laser) that emits laser light
substantially through the center of the highly focused and thinly
shaped lobe created by the pencil beam antenna. The laser light is
within the spectrum of visible light and in operation serves as a
guide for directing the highly focused and thinly shaped lobe of
the antenna, which is, as is understood by those skilled in the
art, not visible to the human eye. In order to ensure that the
laser light serves as an accurate guide for aiming the antenna
lobe, an optical light emitter is arranged in front of the pencil
beam antenna so that, in operation, the laser light and the antenna
lobe overlap along the length of the antenna lobe. In some
embodiments, the optical light emitter includes a optical fiber
terminated by a lens end-cap. Those skilled in the art will
appreciate that non-metallic components (such as glass or high
index plastics) arranged in close proximity to the antenna will
have less, if any, impact on the operation of the antenna than
metallic components will have.
[0029] Additionally and/or alternatively, a RFID tag reader in
accordance with aspects of the invention may include a viewfinder
serving as the targeting element for aiming the highly focused and
thinly shaped lobe at a target RFID tag.
[0030] Additionally and/or alternatively, a RFID tag reader in
accordance with aspects of the invention may be incorporated into a
system in which the RFID tag reader is mounted so that the highly
focused and thinly shaped lobe created by the antenna is fixed to
cover a known location and a RFID tag can be read only at that
location. For example, a RFID tag reader provided in accordance
with aspects of the invention may be placed above a portion of a
conveyor belt so as to be able to read/program RFID tags passing by
one at a time on the conveyor belt below.
[0031] Moreover, those skilled in the art will appreciate that
there are many applications for the use and integration of an RFID
tag reader in accordance with aspects of the invention in view of
the following. As such, the following is not provided to restrict
the claims included herein, but is merely provided to help
illustrate aspects of the inventions by providing a detailed
example of those aspects as employed by the inventor in one
embodiment.
[0032] Aspects of the invention may be embodied in a number of
forms. For example, various aspects of the invention can be
embodied in a suitable combination of hardware, software and
firmware. In particular, some embodiments include, without
limitation, entirely hardware, entirely software, entirely firmware
or some suitable combination of hardware, software and firmware. In
a particular embodiment, the invention is implemented in a
combination of hardware and firmware, which includes, but is not
limited to firmware, resident software, microcode and the like.
[0033] Additionally and/or alternatively, aspects of the invention
can be embodied in the form of a computer program product that is
accessible from a computer-usable or computer-readable medium
providing program code for use by or in connection with a computer
or any instruction execution system. For the purposes of this
description, a computer-usable or computer readable medium can be
any apparatus that can contain, store, communicate, propagate, or
transport the program for use by, or in connection with, the
instruction execution system, apparatus, or device.
[0034] A computer-readable medium can be an electronic, magnetic,
optical, electromagnetic, infrared, or semiconductor system (or
apparatus or device) or a propagation medium. Examples of a
computer-readable medium include a semiconductor and/or solid-state
memory, magnetic tape, a removable computer diskette, a random
access memory (RAM), a read-only memory (ROM), a rigid magnetic
disk and an optical disk. Current examples of optical disks
include, without limitation, compact disk--read only memory
(CD-ROM), compact disk--read/write (CD-R/W) and DVD.
[0035] In accordance with aspects of the invention, a data
processing system suitable for storing and/or executing program
code will include at least one processor coupled directly or
indirectly to memory elements through a system bus. The memory
elements can include local memory employed during actual execution
of the program code, bulk storage, and cache memories which provide
temporary storage of at least some program code in order to reduce
the number of times code must be retrieved from bulk storage during
execution. Additionally and/or alternatively, in accordance with
aspects of the invention, a data processing system suitable for
storing and/or executing program code will include at least one
processor integrated with memory elements through a system bus.
[0036] Input/output (i.e. I/O devices) including but not limited to
keyboards, touch-pads, displays, pointing devices, etc.--can be
coupled to the system either directly or through intervening I/O
controllers.
[0037] Network adapters may also be coupled to the system to enable
communication between multiple data processing systems, remote
printers, or storage devices through intervening private or public
networks. Modems, cable modems and Ethernet cards are just a few of
the currently available types of network adapters.
[0038] FIG. 1 is a schematic view of a Radio Frequency
Identification (RFID) tag reader 100 provided in accordance with
aspects of the invention. Those skilled in the art will appreciate
that the RFID tag reader may be supported by a suitable combination
of hardware, software and firmware, in addition to mechanical
structures and packaging. But only those elements required to
describe specific aspects of the invention have been illustrated in
FIG. 1. Specifically, the RFID tag reader 100 includes a transmit
signal chain 110 and a receive signal chain 130. Both the transmit
signal chain 110 and the receive signal chain 130 are coupled
through a circulator 120 to an antenna 141. The circulator 120 is
provided to selectively couple the transmit signal chain 110 and
the receive signal chain 130 to the antenna 141. Those skilled in
the art will appreciate that the circulator 120 may be replaced by
a multiplexer (MUX) or switching circuit in order to achieve
substantially the same result.
[0039] The antenna 141 is a pencil beam antenna designed to provide
a highly focused and thinly shaped lobe 142 (i.e. antenna beam
pattern). The RFID tag reader 100 includes a controller 103 also
connected to each of the transmit signal chain 110 and the receive
signal chain 130. A user interface 101 is further connected to the
controller 103.
[0040] In the specific example embodiment illustrated in FIG. 1,
the RFID tag reader 100 includes an unmodulated laser light source
105 for providing a laser light utilized to aim the highly focused
and thinly shaped lobe 142. The unmodulated laser light source 105
is coupled to an optical fiber 105a that is terminated with a lens
end-cap 105b, which is arranged in front of the antenna 141 so that
the laser light 106 emitted through the lens end-cap 105b is
directed through the center of the highly focused and thinly shaped
lobe 142 along the length thereof. Those skilled in the art will
appreciate that the combination of the unmodulated laser light
source 105, optical fiber 105a and the lens end-cap 105b suitably
arranged form a means for aiming the highly focused and thinly
shaped lobe 142 created by the antenna 141. The antenna 141 and the
lens end-cap 105b may be provided in an integrated package 150 to
maintain accurate alignment of the laser light 106 and the antenna
lobe 142. Again, those skilled in the art will appreciate that the
laser light 106 is visible, while the highly focused and thinly
shaped lobe 142 created by the antenna 141 is not visible to the
human eye, and that the laser light 106 serves to aim the antenna
lobe 142. Additionally and/or alternatively, the unmodulated laser
light source 105 may be replaced with another means of aiming the
highly focused and thinly shaped lobe 142, as described above.
[0041] With continued reference to FIG. 1, the transmit signal
chain 110 includes a RF/microwave oscillator 117. An output of the
oscillator 117 is coupled to a mixer/modulator 113. The
mixer/modulator 113 is also coupled to receive an analog input from
a digital-to-analog converter 111, which is itself coupled to
receive a digital signal from a controller 103. The output of the
mixer/modulator 113 is coupled into a pre-transmission power
amplifier 115 before being sent to the circulator 120.
[0042] In operation, the transmit signal chain 110 converts a
digital communication signal from the controller 103 into an analog
communication signal at a RF frequency that can be transmitted by
the antenna 141. In some very specific embodiments, the band of RF
frequencies chosen for operation is in one of the ISM (industrial,
Scientific and Medical) bands defined by the International
Telecommunications Union (ITU). Additionally and/or alternatively,
any RF band can be used that does not interfere with RF frequencies
used for other types of wireless communication.
[0043] The receive signal chain 130 is coupled to receive an input
from the antenna 141 via the circulator 120, and an input from the
oscillator 117 of the transmit signal chain 110. The input from the
circulator 110 is passed through a band pass filter 131. The output
of the band pass filter 131 is in turn coupled in series to a low
noise amplifier (LNA) 132 and receive-side pre-amplifier 133. The
output of the receive-side pre-amplifier 133 is coupled to a
down-converter 134, which may be embodied as a mixer similar to the
mixer 113. In series, after the down-converter 134, the receive
signal chain 130 includes an IF (intermediate frequency) filter
135, a post-amplifier 136, which is then coupled to the
Analog-to-Digital Converter (A/D) 137 The output of the A/D 137 is
coupled into the receiving digital signal processor (not shown)
within the controller 103. In operation, the receive signal chain
130 receives and delivers down-converted communication signals
received by the antenna 141.
[0044] Additionally and/or alternatively, the output of the
receive-side pre-amplifier 133 can be split into I and Q (i.e.
in-phase and quadrature branches respectively) branches. The I and
Q branches can be substantially identical to the remainder of the
receive signal chain 11 0 described above. I-Q detection permits
the subtraction of clutter from the raw return more effectively
than other methods such as envelope detection. However, I-Q
detection requires more complex hardware.
[0045] Turning to FIG. 2, provided is an illustration depicting a
method of use of a RFID tag reader 100' in accordance with aspects
of the invention. For the sake of this example only, the RFID tag
reader 100 illustrated in FIG. 2 contains all of the components
shown in the RFID tag reader 100 shown in FIG. 1. The illustration
in FIG. 2 depicts a very specific scenario to help explain aspects
of the invention and is not meant to limit applications of RFID tag
readers created in accordance with aspects of the invention. The
illustration in FIG. 2 includes a user 50 using the RFID tag reader
100', that has been provided in accordance with aspects of the
invention. That is, with further reference to FIG. 1, the RFID tag
reader 100' includes the pencil beam antenna 141 and lens end-cap
105b, which is internally connected to the laser source 105 (not
shown in FIG. 2). The RFID tag reader 100' additionally includes a
user interface provided in the form of a keypad 160 and a display
162. The user interface depicted is provided as an example only,
and in other embodiments, the user interface may include a similar
or different combination of features. Again, in operation, the RFID
tag reader 100' emits a highly focused and thinly shaped lobe 142
(as previously shown in FIG. 1), which is created by the pencil
beam antenna 141, and a laser light 106, which is emitted from the
lens end-cap 105b and is aligned with the lobe 142.
[0046] The illustration in FIG. 2 also includes a number of boxes
201, 202, 203, 204, 205, 206, 207, 208, each having a respective
RFID tag 201a, 202a, 203a, 204a, 205a, 206a, 207a and 208a affixed
thereon. In operation, a conventional RFID tag reader would not be
able to selectively communicate with any of the RFID tags 201a,
202a, 203a, 204a, 205a, 206a, 207a and 208a, and would instead be
forced to communicate with all of them. In contrast, the RFID tag
reader 100', having the pencil beam antenna 141, can be used to
selectively communicate with any of the RFID tags 201a, 202a, 203a,
204a, 205a, 206a, 207a and 208a to the exclusion of the others. In
FIG. 2, the user 50 is shown selecting box 201 with corresponding
RFID tag 201a using the RFID tag reader 100'. This is accomplished
by aligning the laser light 106 over at least a portion of the RFID
tag 201a, thereby also aligning the highly focused and thinly
shaped lobe 142 with the antenna lobe created by the antenna (not
shown) within the RFID tag 201a. Likewise, any of the other RFID
tags 202a, 203a, 204a, 205a, 206a, 207a and 208a may be selected in
the same way.
[0047] FIG. 3 is a first flow chart illustrating general method
steps for operating a RFID tag reader in accordance with aspects of
the invention. Starting at step 3-1, the method includes visually
identifying a RFID tag to read/program with the RFID tag reader
configured in accordance with aspects of the invention. At step 3-2
the method includes pointing a laser guide at the selected RFID
tag, thereby aligning a highly focused and thinly shaped lobe
created by a pencil beam antenna (the antenna) utilized by the RFID
tag reader directly over the RFID tag and within the lobe of the
antenna in the RFID tag. Since RFID tags have comparably low
available transmission power the lobe of the antenna in the RFID
tag will be relatively small. As a result, communication between
the RFID tag reader and selected RFID tag will occur by way of the
overlap of the highly focused and thinly shaped lobe created by the
pencil beam antenna utilized by the RFID tag reader and the
relatively small lobe created by the antenna in the selected RFID
tag. Other RFID tags proximate to the selected RFID tag will not be
able to establish a communication link with the RFID tag reader
because the lobes created by their respective antennas will not
effectively overlap with the highly focused and thinly shaped lobe
created by the antenna included in the RFID tag reader. However,
there may be an exception to this if the RFID tag selected is very
close to another RFID tag, and in which case it may have not been
possible to visually distinguish a separation between the two tags
in the first place. Finally, at step 3-3, the method includes
communication between the RFID tag reader and the selected RFID
tag, with the exclusion of other RFID tags in the area.
[0048] FIG. 4 is a second flow chart illustrating method steps for
operating a RFID tag reader in accordance with aspects of the
invention. Starting at step 4-1, the method includes visually
identifying a RFID tag to read/program with the RFID tag reader
configured in accordance with aspects of the invention. At step
4-2, the method includes aiming the highly focused and thinly
shaped lobe created by the pencil beam antenna, thereby aligning
the highly focused and thinly shaped lobe directly over the RFID
tag and within the lobe of the antenna in the RFID tag. As noted
above, aiming the highly focused and thinly shaped antenna lobe may
include the use of a laser light aligned with the lobe.
Additionally and/or alternatively, a viewfinder or another
mechanical means of aligning the antenna lobe may be utilized.
[0049] At step 4-3, the method includes the exchange of
identification keys between the RFID tag reader and the selected
RFID tag. The use of identification keys, such as for example,
encryption keys, may serve to provide a level of security to the
communication between the RFID tag reader and the selected RFID
tag. In such embodiments, the RFID tag reader, in addition to other
stored information, would have to store a local identification key
and have a processor programmed to manage the exchange of
identification keys with a RFID tag.
[0050] Once the identification keys are exchanged, at step 4-3, the
method includes determining whether or not communication between
the RFID tag reader and the selected RFID tag is authorized. If
communication is not authorized (no path, step 4-4), at step 4-5
the method includes displaying a "no authorization" message to the
user of the RFID tag reader or otherwise providing a failure to
authenticate message to a user or system utilizing the RFID tag
reader. If communication is authorized (yes path, step 4-4), at
step 4-6 the method includes enabling communication between the
RFID tag reader and the RFID tag in which protected information
between the two is exchanged.
[0051] While the above description provides example embodiments, it
will be appreciated that the present invention is susceptible to
modification and change without departing from the fair meaning and
scope of the accompanying claims. Accordingly, what has been
described is merely illustrative of the application of aspects of
embodiments of the invention and numerous modifications and
variations of the present invention are possible in light of the
above disclosure.
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